The Tour de France entered the Pyrenees on Thursday, and the Schlecks delivered a 1-2 punch with attacks at the end of the 131-mile Stage 12 from Cugnaux to the Luz-Ardiden ski station. By the finish, Contador was gritting his teeth.

Spanish climbing specialist Samuel Sanchez, whose team is based in nearby Basque country, gave the home crowd reason to celebrate. He won the stage after riding inspired through a sea of red, green and white Basque flags.

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And the current darling of French cycling -- Thomas Voeckler -- surprised himself by keeping the yellow jersey on Bastille Day after scaling three punishing peaks.

Sanchez and Voeckler, however, aren't expected to be among the contenders for the title when the three-week cycling showcase ends July 24 on Paris' Champs-Elysees.

Contador and Andy Schleck -- and maybe his brother -- are. That'll be after the race runs through more punishment in the Alps in Week Three and a pivotal individual time trial in Grenoble on the next-to-last race day.

Thursday's leg showed that the once indomitable Contador, who had a dismal Tour start because of crashes and stumbles at his Saxo Bank team, can be vulnerable in the mountains.

Frank Schleck could be an ace-in-the-hole for his brother and Leopard Trek teammate, who was runner-up to Contador each of the last two years. Last year, Andy didn't enjoy any brotherly benefit: Frank crashed in a nasty cobblestone patch in Stage Three and dropped out of the race with a broken collarbone -- missing the mountain stages.

On Thursday, the pack scaled the Hourquette d'Ancizan, an ascent making its Tour debut. Then came the fabled Col du Tourmalet pass and the ride up to Luz-Ardiden -- both among the toughest climbs in cycling.

In Tour lore, the Luz-Ardiden climb is remembered as the place where Lance Armstrong tumbled in 2003 after his handlebars were caught on a fan's outstretched bag. The Texan got back up, rode like a man possessed and won the stage -- on way to the fifth of his record seven Tour victories.

Thursday's drama also came on the finale up to Luz-Ardiden.

Sanchez, trailed closely by Belgian rider Jelle Vanendert, overtook a group of breakaway riders up Luz-Ardiden and mustered a final burst of speed to win their two-man sprint in the last few hundred yards.

Farther back, Frank -- helped at times by Andy -- repeatedly attacked the favorites on the 8.3-mile ascent to the ski station and came away with a third-place finish in the stage -- 10 seconds behind Sanchez.

Andy trailed 20 seconds later, and Contador huffed and puffed through the finish another 33 seconds back of the elder Schleck.

The deficit wasn't enough to seriously dent Contador's ambitions for a three-peat -- and he says he's not at his best yet -- but the performance by the Schleck brothers did send a signal.

"I was a bit careful," the three-time Tour champion said. "I saw the Schlecks were discussing together and that they were going to play their cards. Frank was the stronger -- and both of them attacked.

"But I'm nevertheless happy with this first mountain stage," Contador said. "Each day, I feel better ... I still don't have my best legs. I'm not riding with the same rhythm, but it's encouraging."

Still, Andy Schleck sensed weakness from the Spaniard.

"I think today was a perfect day for us. ... For sure, this is not a decisive stage, but we showed we are here," he said. "Contador is not unbeatable -- he lost more time today.

"We had a discussion with Frank and we decided to attack. I attacked, Frank attacked, we played it like this. Then it was time for him to go all out," he added. "If we keep going like this, we can win."

More than halfway through the race, the seconds Contador has lost due to both mishaps and lack of luck are adding up: Overall, he trails Voeckler by four minutes, in seventh place.

After 11 stages on wind-swept flats and rolling hills that favored sprinters and breakaway riders, the mountains were expected to separate the overall race contenders from the rest of the pack.

And up to billing, Thursday's punishing climbs whittled down the list of title hopefuls: Nine riders are now within five minutes of the leader -- half as many as a day earlier. Some hopes of victory vanished on the first mountain day.

"I'm glad I was wrong," he said with a smile. "Keeping the jersey was far from expected as the stage started today. ... You have to believe that the yellow jersey gives you a bit of added inspiration on the Bastille Day."

On the climb up the Col du Tourmalet, a string of better-known riders -- including some potential title contenders -- dropped behind the pack: Among them, Dutch rider Robert Gesink, Germany's Tony Martin, and Spain's Luis Leon Sanchez, who was second overall as the day began.

A few crashes marred the day's ride. Speeding downhill, Olympic pursuit gold medalist Geraint Thomas crashed right after the Welsh rider passed his national flag hoisted by one of the thousands of roadside fans.

Moments later, the Team Sky rider again lost control and skidded off the road. But in a show of grit, Thomas battled back to rejoin the breakaway group, and by midway up the Tourmalet, had briefly taken the lead alone.

By the end, however, the Welshman sputtered up the Luz-Ardiden climb and finished 36th -- 5:20 behind Sanchez. He's 25th overall, 10:21 back of the French race leader.

RadioShack's Andreas Kloeden of Germany, who was already nursing back pain from a mass pileup in Sunday's stage in central France, fell again Thursday and was treated by a race doctor on both elbows during the stage. Kloeden finished 8:26 back of Sanchez, all but ending any title hopes that he might have had: He's 10:19 behind Voeckler in 24th place.

Two more grueling Pyrenean stages loom on Friday and Saturday, starting with Stage 13's 95-mile ride from Pau to Lourdes featuring the Col d'Aubisque climb.